Chromatin isolated from normal and oncornavirus-transformed malignant cells will be used to raise antisera in rabbits. These antisera will then be used to study the immunochemistry of the chromatins and chromatin-associated proteins using micro-complement fixation and other immunological techniques. Chromatin and chromatin sub-fractions will be examined for the presence of common and individually-specific proteins by immunologic techniques employing absorbed antisera. Proteins unique to chromatin from a particular source will be isolated by affinity chromatography and characterized biochemically. Antisera will be prepared against the isolated proteins and used to study the relationship of these proteins to the malignant state.